Reflection Prism Research Articles

Design of ghost-free aerial display by using prism and dihedral corner reflector array

In a dihedral corner reflector array (DCRA) used as an aerial display, the observer can directly touch aerial images. However, in this optical element, the visibility of the aerial image is reduced by stray light, called a ghost. Although ghost formation can be suppressed using a louver, the viewing angle and brightness of the aerial image also decrease. This paper proposes the design of a ghost-free aerial display using a prism and DCRA. Based on experimental results, the ghost brightness with the proposed method was only about 14% of the DCRA at front. In addition, the aerial image produced by the proposed device was the brightest for 0–20°.

Dynamic full-field refractive index distribution measurements using total internal reflection terahertz digital holography

Massive usage scenarios prompt the prosperity of terahertz refractive index (THz RI) measurement methods. However, they are very difficult in measuring the full-field dynamical RI distributions of either solid samples without a priori thickness or liquid samples. In this study, we propose total internal reflection THz digital holography and apply it for measuring RI distributions for both solid and liquid samples dynamically. An RI measurement model is established based on an attenuated total reflection prism with a pitching angle. The pitching angle and the field of view can be numerically calculated from the spectrogram of the off-axis Fresnel hologram, which solves the adjustment of the visually opaque prism irradiated by the invisible THz beam. Full-field RI distributions of the droplets of solid-state soy wax and distilled water are obtained and compared with THz time-domain spectroscopy. The evaporation of an ethanol solution droplet is recorded, and the variation of the RI distribution at the sample–prism interface is quantitatively visualized with a temporal resolution of 10 Hz. The proposed method greatly expands the sample range for THz RI measurements and provides unprecedented insight into investigating spontaneous and dynamic THz phenomena.

Thermal model of a photovoltaic module with heat-protective film

Research on reducing the working temperature of PV modules is gaining attention to improve their electrical performance, efficiency, and life especially in warm climatic conditions. This study describes the use of novel heat-protective film based on holographic coating with a total internal reflection prism layer applied to maintain the operating temperature of the photovoltaic module. A mathematical model of thermal protection based on the holographic film is described. MATLAB/Simulink simulation was used to estimate the current-voltage and output power–solar irradiance characteristics of a photovoltaic module with and without holographic film. Regression models were developed based on field testing to determine a relationship between the temperature of heat-protected/unprotected PV panels and ambient temperature. The results showed that a temperature reduction of 3.54 °C is obtained for solar modules with thermal protection film compared to the one without holographic film. The modeling and field performance results confirm the effectiveness of the thermal protective film in reducing the temperature and improving the photovoltaic panel performance in hot climates.

Тенденції розвитку сенсорних приладів на основі поверхневого плазмонного резонансу

Trends in the development of modern sensory devices based on surface plasmon resonance (SPR) are considered. The basic principles of construction of SPR sensor are given. For excitation of surface plasmons on the surface of sensitive elements of biosensory, a prism of total internal reflection is used or a dielectric substrate are used. A thin (dozens nm) film of high-conductive metal (mainly gold or silver) is applied to the working surface of the prisms or dielectric substrate. In a typical observation experiment, SPR is measured dependence on the angle of increasing light intensity, reflected by the resonance sensitive surface of the prism (chip). The optical schemes and principles of work of various SPR sensors are considered: - SPR Sensors with angular modulation, which are the most commonly used method based on the corner registration, in which the SPR occurs. The surface of the metal film is irradiated by monochromatic light and scans on a certain range of angles. There is a kind of SPR sensors with angular modulation, in which there is no mechanical scan of the angle of fall. Such sensors are entirely necessary for excitation of PPRs a set of angles is obtained due to a divergent or convergent light beam. - PPR sensors with a wavelength modulation is based on fixing an angle of falling light at a certain value and modulation of the wavelength of the incident light. Excitation of surface plasmons leads to a characteristic failure in the spectrum of reflected radiation. - Phase sensitive SPR sensors in which a change in the phase of the light wave associated with the surface plasma is measured on one corner of the fall and the wavelength of the light wave and is used as the output signal. - SPR imaging sensors in which the Technology of SPR imaging (SPRi) combines the sensitivity of the SPR with spatial image capabilities. The SPRI circuit uses as a fixed angle (as a rule, a slightly left angle of the SPR) and a fixed wavelength to measure changes in the reflection ability (Δ% R) that occur when the curve of the SPR is shifted due to the change in the refractive index above the surface of the sensor element. - SPR imaging sensors polarization contrast. In order to improve the quality of high-performance SPR imaging sensors in terms of sensitivity and resolution, the method of polarization contrast is used Disadvantages and advantages of SPR sensors are constructed with different principles are considered. The design and prospect of the use of achromatic and suburchast wave plates in the PPR imaging sensors with polarization contrast are considered.

A New Method for Auto-Inspecting Both Opposite Surfaces of Tec Components Based on Equal-Optical-Path Imaging System

An new optical method for simultaneously inspecting opposite surfaces defects of thermoelectric cooler (TEC) components that meets condition of equal optical paths for both surfaces imaging has been proposed. The optical apparatus for surfaces defects inspection has been designed and established with “confocal” imaging system consisting of two trapzoid reflection prisms and one optical images combiner. Experimental investigations on defects inspection with the “confocal” imaging system have been carried out. The results showed that the proposed optical method can be used to simultaneously inspect the defects of opposite surfaces of TEC components without need to employ a tele-centric imaging lens with large depth of focus. It was concluded that the optical inspection method can meet the technical requirements for inspecting opposite surfaces (both side surfaces, or both top and bottom surfaces) defects of TEC components and has advantages of equal good imaging quality, increased inspection accuracy and throughput, simplified system configuration and improved system reliability etc.

Theoretical investigation of two-dimensional sub-wavelength structures fabricated by multi-beam surface plasmon interference lithography

In this study, multi-beam surface plasmon (SP) interference lithography was theoretically proposed and demonstrated to fabricate periodic two-dimensional sub-wavelength structures. The lithography structures were based on an attenuated total reflection prism used to excite the SPs using a 442 nm laser. Circular lattices with periods of 166 and 288 nm were successfully obtained via three- and six-beam SP interference lithography, respectively; these lattices exhibited an identical feature size of 96 nm. Square dot arrays with a 177 nm period and 88.5 nm spot size were obtained by four-beam SP interference lithography. The proposed lithography technology has a simple structure and is economical; further, it may provide an effective method for the fabrication of two-dimensional sub-wavelength structures.

Novel solar‐powered thermoelectric‐based mobile charger with the capability of operating with different small refractive/reflective concentrators

The output power of a thermoelectric module (TEM) is not high enough to harvest trivial heat, so it cannot be used to directly harvest solar heat. In this study, a novel method is proposed to utilize a TEM to directly harvest solar energy. The proposed scheme is to attach a small refractive/reflective concentrator to the hot surface of the TEM. In this regard, a novel solar-powered thermoelectric-based mobile charger has been built to provide experimental verification. Four different small concentrators with similar size; a refractive compound parabolic concentrator (CPC), a reflective CPC, a refractive prism concentrator and a reflective prism concentrator are considered to attach to the TEM of the built mobile charger. The theoretical basis of the proposed idea is formulated by presenting new formulas proved and given for the first time in this study. It is shown that in theory, attaching the four mentioned small concentrators to the TEM increases the power production of the TEM of the charger by 1712%, 1941%, 2083% and 1797%, respectively. Experimental results are presented that verify theoretical concepts and calculations presented in this work. Comparing the proposed technique realized in this study with two available techniques (direct and indirect techniques) reported in the literature substantiates the novelty and contributions of this work.

Design analysis and test verification of a rigid-flexible, dual-mode coupling support structure for space-based rectangular curved prisms.

In view of the functional requirements of high reliability and stability support of optical components of space remote sensors, a rigid-flexible, dual-mode coupling support structure for space-based rectangular curved prisms (SRCPs) was designed. In-depth studies of the support principle and engineering realization of the SRCPs and optimization of the flexible adhesive structure were performed. Static and dynamic simulations were conducted on the mirror subassembly by means of finite element analysis, and test verification was also performed. The tests revealed that the surface shape error of the mirror subassembly after mechanical testing was 0.021λ, the displacement of the mirror body was 0.008 mm, the inclination angle was ∼0.8'', the mass of the mirror subassembly was 4.79 kg, the fundamental frequency was 283 Hz, and the maximum amplification of the total rms acceleration was 4.37. All indexes were superior to those of the design requirements. On this basis, bonding tests and mechanical tests of a rectangular curved prism reflector, a rectangular curved prism, and a rectangular plane reflector employing this proposed support structure were continued. The test results verified the reliability, stability, and universal applicability of the proposed rigid-flexible, dual-mode peripheral bonding support structure.

High-contrast ratio and high-efficiency anamorphic DLP illumination system design with a freeform surface lens.

In this paper, an anamorphic digital light processing illumination system design with a freeform surface lens is described. A lens with a freeform surface lens is combined with the achromatic total internal reflection prism set for application in a relay lens system. In order to achieve a high contrast ratio without sacrificing illumination system efficiency, the novel, to the best of our knowledge, design uses an x-y polynomial surface for the freeform surface lens to reduce the overlap angle of the anamorphic angular distribution in angular space. Moreover, there is no need to use a baffle at the aperture stop in this novel design. We can reach a half-cone angle of 17.49° in the y direction of the angular distribution in angular space. The overlap angle is only 0.98°. Finally, with this novel design, we can achieve a high contrast ratio of 9128:1 and an illumination system efficiency is 66.4%. The four-corner average spot size at the active area of the digital micromirror device chip is controlled at about 240 µm, and the optical distortion is less than 1%. The corresponding lateral color aberration is 3.61 µm.

Three-zone multifocus hybrid Fresnel lens concentrator.

In this paper, we designed a three-zone multifocus hybrid Fresnel lens concentrator without a homogenizer. This concentrator uses three types of prisms: a refractive prism, a single total internal reflection (STIR) prism, and a double TIR (DTIR) prism. In order to achieve a uniform irradiance distribution, the Fresnel lens is cut into four quadrants and reconnected. Moreover, by decreasing the angle of the edge ray, the hot spot effects caused by the STIR and DTIR prisms can be reduced. Finally, the three-zone multifocus hybrid Fresnel lens concentrator can achieve a geometric concentration ratio of 2121X, f-number of 0.441, optical efficiency of 76.570%, acceptance angle of ±0.268∘, uniformity of 57.002%, and hot spot criteria of 1.369.

Common path continuous terahertz reflection and attenuated total reflection imaging

Terahertz imaging technology is one of the candidate technologies for medical imaging. In particular, continuous terahertz reflection and attenuated total reflection imaging are expected to achieve rapid intraoperative imaging, which is hot research topic at present. In order to realize the rapid multi-dimensional and high-quality terahertz imaging detection of sample, it is necessary to study the common optical path continuous terahertz reflection/attenuated total reflection dual-mode imaging system based on point scanning. By using the Fresnel formula and the penetration depth formula of evanescent wave, the influence of imaging angle on the reflected signal and the penetration depth of attenuated total reflection are studied theoretically in this paper. The imaging angle of terahertz wave suitable for both reflection and attenuation total reflection imaging is obtained. Based on this, an isoscele total reflection prism with a base angle of 49° is designed. The dual-mode imaging of common optical path continuous terahertz reflection and attenuated total reflection is realized by quickly switching between reflection window and total reflection prism. The reflection and attenuation total reflection imaging modes have imaging resolutions of 400 μm and 500 μm, respectively. Continuous terahertz reflection and attenuated total reflection imaging are experimentally studied by using distilled water and pork as samples. The results show that the relative reflectance of the sample obtained in the attenuated total reflection imaging mode fluctuates within a range of 1%, and the image contrast is 9 times that of the reflection imaging mode. Moreover, attenuated total reflection imaging can effectively identify the sample with the length less than 1 mm. Thus, compared with reflection imaging, continuous terahertz attenuated total reflection imaging has the advantages of high image resolution, high image contrast and highr signal stability, and can accurately obtain the reflectivity of sample. The terahertz attenuated total reflection imaging technology is more helpful in achieving high sensitivity imaging of samples. By combining reflection and attenuated total reflection imaging modes, the advantages of different imaging modes can be compensated for and the performance of the imaging system can be further improved. This common path continuous terahertz reflection and attenuated total reflection dual mode imaging system is expected to achieve a high sensitivity detection of sample.

Miejsce tradycji. Refleksja autobiograficzna Wilhelminy Zyndram­‑Kościałkowskiej

The paper is an attempt at showing – through the prism of autobiographical reflection – the location of tradition, as understood by Wilhelmina Zyndram‑Kościałkowska (1844–1926), a translator, writer and literary critic. The notion of location is understood by the author as a particular, restricted, time‑spatial reservoir of meanings, perceived in a broader perspective, that is as a component of a larger whole. The location of tradition is a segment and stage concerning a problem residuum of meanings in culture and history, as well as in the history of thought, which has been located in the space of individual biography of Kościałkowska, constructed with an old hand of the writer and placed as a component of diagnoses in her contemporaneity. The research material includes manuscripts (notebooks with memories and other types of autobiographical archives), deposited in the Lithuanian State Historical Archives in Vilnius (Lietuvos Valstybės Istorijos Archyvas). The author shows various ways of conducting dialogue by the critic with the old tradition (history, politics, culture, portraits of people, literature, art, family history) and the meaning of the location of tradition in the process of recording oneself and one’s contemporaneity by Kościałkowska.

Quantum-synergetic ontology of generalized corporeality (II): post-nonclassics, temporality, and reflection of acting

In this article, the author advances the idea of generalized corporeality in its functional manifestations in the acts of communication, activity, and theatrical art. The work is dedicated to the problem of “smart body”, in other words, conscious and manageable generalized corporeality is one of the core themes in development and self-improvement of acting skills and onstage genuineness. The key problem is the problem of harmony, unity between inner and outside, words and doings, thoughts and actions, realized by the actor just partially, so is by the stage director and audience. The author attempts to describe this problem by means of post-nonclassical philosophical methodology offered by V. S. Stepin, concepts of post-nonclassical practices, synergy of motion and state, which marks the synthesis of the ontologies of states of generalized corporeality and temporal ontologies, introduced in the previous article. The author also attracts the concept of unconscious reflection of V. Lefebvre, which describes a special type of reflection as a certain unconscious component of generalized corporeality that creates a specific interpretation of the skill and work with time in post-nonclassical context. Interpretation of the acquired acting skills that taught in many schools of classical and contemporary theatre, from K. Stanislavski and M. Chekhov to A. Artaud and E. Barba, are also viewed through the prism of reflection of synthetic ontologies of generalized corporeality. In conclusion, the author introduces theatrical interpretation of the twofold activity triad, which allows embracing the relationship between various observers, the actors of theatrical event: actor – stage director – audience.

Dispersion-compensated polarization Sagnac interferometer with high imaging quality

Multistage diffraction of a dispersion-compensated polarization Sagnac interferometer (DCPSI) reduces the fringe visibility of interference fringes generated in a focal plane array, thereby leading to the poor quality of the reconstructed polarization images. In this paper, a double total reflection prism between the DCPSI and imaging lens is added to limit the effect of multistage diffraction and improve the imaging quality. First, the influence of multistage diffraction on the interference fringes and the ratio of fringe amplitude to the background was analyzed. Second, the range of angles of the two right angle prisms was calculated. Simulation and experiment were carried out to prove the superiority of the proposed method. Result shows that the ratio of fringe amplitude to the background increases from 1/5 to 1/3 and from 1/10 to 1/6 in simulation and experiment when a double total reflection prism structure is added respectively. This method can reduce the influence of multistage diffraction on interference fringes and improve the image quality of DCPSI effectively.

Designing an anamorphic illumination system with an RTIR prism for a tilt-and-roll-pixel-type projector.

A relay lens system design for a mini-projector with telecentric illumination is described. The reverse total internal reflection (RTIR) prism for angular magnification and lateral magnification is discussed in detail, and magnifications under different digital micromirror devices (DMD) are compared. The tilt-and-roll pixel (TRP) DMD chip (tilt angle is ${\pm 17}^\circ $±17∘) is the latest spatial light modulator, and the f-number of the illumination system is 1.71. Using the TRP DMD, the lateral magnification and the angular magnification for the RTIR prism can be increased by 3.77% and 8.73% over that obtainable using the conventional DMD chip (tilt angle is ${\pm 12}^\circ $±12∘). In order to solve for the angular magnification of an RTIR prism, the baffle is set at the aperture stop of the relay lens system. There is a trade-off between the efficiency and the contrast ratio with the baffle. When B (the position of the baffle) is at 0.11, the contrast ratio of the illumination system is 7590:1 and the efficiency is 57%. The spot size at the edge and corner of the DMD active area is controlled to be less than 250 µm, and the optical distortion is less than 1%.

Optimized sample addressing in prism-coupled surface plasmon resonance experiments

In this work we study the walk-off of the beam from the interrogation spot during rotation in surface plasmon resonance experiments using prism-based coupling such as the widespread Kretschmann configuration. The impossibility of maintaining a stationary footprint on the sensing surface with a fixed rotation axis can be of high importance. This would be specially so if samples are not homogeneous such as in arrays for multiplexing. By theoretically analyzing the behavior of the walk-off during rotation around an arbitrary fixed axis, we find an optimal and simple configuration to minimize this effect. The proposed setup is experimentally tested to verify the results and to show its ease of implementation. Interestingly, the conclusions reached may also be applied to other techniques employing reflection prisms.

Towards simultaneous observation of path and interference of a single photon in a modified Mach–Zehnder interferometer

Classical wisdom of wave–particle duality regulates that a quantum object shows either the particle or wave nature but never both. Consequently, it would be impossible to observe simultaneously the complete wave and particle nature of the quantum object. Mathematically the principle requests that the interference visibility V and which-path distinguishability D satisfy an orthodox limit of V 2 + D 2 ≤ 1 . The present work reports a new wave–particle duality test experiment using single photons in a modified Mach–Zehnder interferometer to demonstrate the possibility of breaking the limit. The key element of the interferometer is a weakly scattering total internal reflection prism surface, which exhibits a pronounced single-photon interference with a visibility of up to 0.97 and simultaneously provides a path distinguishability of 0.83. Apparently, the result of V 2 + D 2 ≈ 1.63 exceeds the orthodox limit set by the classical principle of wave–particle duality for single photons. We expect that more delicate experiments in the future should be able to demonstrate the ultimate limit of V 2 + D 2 ≈ 2 and shed new light on the foundations of contemporary quantum mechanics.

Tunable-illumination for laser Fourier ptychographic microscopy based on a background noise-reducing system

It is inherently difficult for a conventional microscopic imaging system to produce images with both wide field of view (FOV) and high-resolution because of its limited space bandwidth product. Fourier ptychographic microscopy (FPM) has been developed to overcome this limitation by using angle-varied illumination to enhance the performance of the system. In this paper, we propose a FPM imaging approach that employs a laser source with a newly developed illumination control optical system. The proposed system consists of a digital micromirror device and a zoom system with a condenser lens to provide sample illumination with angle-varied pattern directions and controllable pattern sizes. In addition, a total internal reflection prism is employed in the system to remove unexpected background noise and extend the FOV for reconstruction. The proposed system is validated against a USAF resolution target and a biological sample, and as a result reconstructs images with higher resolution and more details once the positional misalignment correction algorithm is employed. We envision that the proposed FPM system will be suitable for high-speed imaging applications.

A Method for Improving Light Intensity Stability of a Total Reflection Prism Laser Gyro Based on Series Correction and Feedforward Compensation

The instability of scale factor and null shift are closely related to the change of the light intensity of a total reflection prism laser gyro (TRPLG). To improve the light intensity stability, the light intensity stabilization principle of TRPLG was analyzed, and a mathematical model of light intensity stabilization system was established. Aiming at the problem that original system has a long adjustment time, a series correction method of adding a proportional integral differential (PID) link in the forward channel was adopted. According to the third-order optimal design, the original I-type third-order overdamped system was optimized to the new II-type third-order underdamped system, which ultimately improved the system's dynamic and steady-state performance. Feedforward compensation was used to introduce the light intensity disturbance during the longitudinal mode hopping into the closed-loop system, which realized the full compensation of the light intensity error and improved the light intensity characteristics during the longitudinal mode hopping. Combined with the above two methods, experimental results showed that the new system with feedforward compensation improved the light intensity stability by 32% at constant temperature and by 40% at variable temperature, with the TRPLG's bias stability improved by more than 16% at constant temperature and by 22% at variable temperature.

Поляриметрія анізотропного поверхневого шару на склі

Investigating the Stokes vector of light reflected from the surface of the optical glass, the presence of an anisotropic surface layer was established. The phase difference between radiation p- and s-components is revealed, which varies depending on the angle of incidence. This shows a weak anisotropy. Assuming that the anisotropic layer has an increased refractive index due to its chemical-mechanical treatment, it can be considered as some near-surface weakly guiding gradient burried waveguide. The possibility of coming radiation into such a planar waveguide using a coupling total reflection prism was investigated. The inspection showed a violation of the total internal reflection, unequal for p- and s-polarizations, which confirms the presence of the subsurface layer and its anisotropy. The absorption of radiation, which could be compared with the excitation of modes, is small. This is due to the properties of the prism material. Also, higher order modes are absorbed better. There is no significant angular dependence of the polarization degree of the output beam; however, it is higher in the case of s-polarization.